Accessory beam flattening filter for the varian clinac-4 linear accelerator

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiotherapy Devices

Background:

• Linear accelerators are crucial in radiotherapy.
• Accurate radiation dose distribution is essential for effective cancer treatment.
• Surface dose in large radiation fields can be problematic.

Purpose of the Study:

• To introduce and evaluate an accessory beam flattening filter for the Clinac-4 linear accelerator.
• To assess the filter's impact on x-ray beam dose distribution.
• To determine the effect on surface dose in large radiation fields.

Main Methods:

• An accessory beam flattening filter, a brass disk with critical angles, was attached to the linear accelerator's shadow tray.
• The filter intercepts the x-ray beam before it reaches the patient.
• Dose distribution was analyzed, focusing on large fields near the skin surface.

Main Results:

• The accessory filter effectively eliminated higher dose areas at the edges of large fields.
• Improved x-ray beam dose distribution within the patient was observed.
• A reduction in dose to normal tissues near the skin surface was achieved.

Conclusions:

• The accessory beam flattening filter is an effective tool for optimizing radiation therapy.
• It enhances treatment efficacy by improving dose conformity.
• This device contributes to reduced side effects by sparing normal tissues.